guess vs guesswork

guess and guesswork both are nouns.

Word	Noun	Adjective	Verb	Adverb
guess	Yes	No	Yes	No
guesswork	Yes	No	No	No

As nouns, guess and guesswork are synonyms defined as:

Other synonyms of guess include dead reckoning, guessing, shot.

guess (noun)	guesswork (noun)
an estimate based on little or no information	an estimate based on little or no information
a message expressing an opinion based on incomplete evidence

guess (verb)	guesswork (verb)
expect, believe, or suppose
judge tentatively or form an estimate of (quantities or time)
guess correctly; solve by guessing
put forward, of a guess, in spite of possible refutation